Antonio Largo

Antonio Largo
Universidad de Valladolid | UVA · Department of Physical Chemistry and Inorganic Chemistry

About

164
Publications
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2,387
Citations
Citations since 2016
26 Research Items
555 Citations
2016201720182019202020212022020406080
2016201720182019202020212022020406080
2016201720182019202020212022020406080
2016201720182019202020212022020406080

Publications

Publications (164)
Article
Herein, we report a computational investigation of the binding affinity of dexamethasone, betamethasone, chloroquine and hydroxychloroquine to SARS-CoV-2 main protease using Molecular and Quantum Mechanics as well as Molecular Docking methodologies. We aim to provide information on the anti-COVID-19 mechanism of the abovementioned potential drugs a...
Preprint
Context. Cyanoacetamide is a –CN bearing molecule that is also an amide derivative target molecule in the interstellar medium. Aims. The aim of our investigation is to analyze the feasibility of a plausible formation process of protonated cyanoacetamide under interstellar conditions and to provide direct experimental frequencies of the ground vibra...
Article
Full-text available
Recently, the first Ca-bearing molecule discovered in space, calcium isocyanide, CaNC, has been detected in the IRC+10216 circumstellar envelope. Related to CaNC are closed-shell stable molecules of [C, Ca, H, N] composition. One of the isomers with this composition is hydrocalcium isocyanide, HCaNC, which belongs to the hydrometal isocyanide/cyani...
Article
We present a computational study of the different conformers of amino acetaldehyde. This molecule is a precursor of glycine and also an isomer of the detected molecules acetaldehyde and methylformamide. In addition, a previous theoretical result shows that amino acetaldehyde could be formed from the gas phase reaction of formamide with CH$_{5}^{+}$...
Article
A novel approach has been developed to synthesize complex organic molecules (COMs) relevant to prebiotic chemistry, using Infra‐Red (IR) radiation to trigger the reaction. A laboratory reactor working at low gas density and using IR irradiation was developed to give a hint on what pathways could happen in space conditions. In this way, glycine, the...
Preprint
We present a computational study of the different conformers of amino acetaldehyde. This molecule is a precursor of glycine and also an isomer of the detected molecules acetaldehyde and methylfor-mamide. In addition, a previous theoretical result shows that amino acetaldehyde could be formed from the gas phase reaction of formamide with CH + 5. Dif...
Preprint
p>In the present study, we have shown for the first time how glycine can be synthesized under prebiotic-like conditions using an Infra-Red laser to trigger the reaction. In particular, we observed that in the low-density conditions it can be obtained from simple ion-molecule reactions of acetic acid and protonated hydroxylamine. This reaction, stud...
Article
Full-text available
The metallic cyanoacetylides LiC3N, NaC3N, MgC3N, and CaC3N have been investigated by combined spectroscopy measurements and theoretical calculations. The theoretical calculations predict for the four species that the linear isomer with the formula MCCCN (M = Li, Na, Mg, and Ca) is the most stable one. We used laser ablation molecular beam Fourier...
Article
A computational study of protonated glycine isomers with [H6C2O2N]⁺ molecular formula has been carried out. All of them are possible products of the reaction between protonated hydroxylamine and acetic acid. All reaction processes that could form the [H6C2O2N]⁺ isomers considered in this work are exothermic except for those initiated by the most st...
Article
A theoretical study of the [C, Ti, H, N] isomers, which are species of possible interstellar interest, has been carried out. We have employed different ab initio and density functional theory methodologies. Eleven isomers on the singlet, triplet, and quintet potential energy surfaces (PES) are characterized. The three most stable isomers of this sy...
Article
A previous theoretical study shows that imine acetaldehyde can be obtained from the reaction between protonated vinyl alcohol and azanone. Therefore, imine acetaldehyde could be considered as a good molecule candidate to be found in space and could evolve to more complex organic molecules of prebiotic interest. In this work, we carried out a comput...
Poster
Full-text available
A computational kinetics study of the antioxidant activity of tryptamine toward HO • and HOO • radicals in water at 298 K has been carried out. Density functional methods have been employed for the quantum chemical calculations and conventional transition state theory was used for rate constants evaluation. Different mechanisms have been considered...
Poster
INTRODUCTION One lively discussion in interstellar chemistry goes round the possibility of finding bio-molecules in astronomical sources. Amino acids deserve particular attention, because these biological molecules are building blocks of life, and they have been searched for in space. Despite intensive radiaoastronomical searches, even the simplest...
Article
Full-text available
A computational kinetics study of the antioxidant activity of tryptamine toward HO● and HOO● radicals in water at 298 K has been carried out. Density functional methods have been employed for the quantum chemical calculations and conventional transition state theory was used for rate constants evaluation. Different mechanisms have been considered:...
Article
In the present work we investigated the reaction dynamics that will possibly lead to the formation of protonated glycine by an ion-molecule collision. In particular two analogous reactions were studied: NH3OH⁺ + CH3COOH and NH2OH2⁺ + CH3COOH that were suggested by previous experiments to be able to form protonated glycine loosing a neutral water mo...
Article
A theoretical study of the monoboronyl compounds of second-row elements, [XBO] (X=Na, Si, P, S, Cl), has been carried out. It is observed that the preference for the XBO arrangement is higher when moving to the right of the period. In the case of sodium monoboronyl three minima were characterized, all lying rather close in energy: linear NaBO, line...
Article
Full-text available
Context. Many organic molecules have been observed in the interstellar medium thanks to advances in radioastronomy, and very recently the presence of urea was also suggested. While those molecules were observed, it is not clear what the mechanisms responsible to their formation are. In fact, if gas-phase reactions are responsible, they should occur...
Article
Context. Knowing how the molecules that are present in the ISM can evolve to more complex ones is an interesting topic in interstellar chemistry. The study of possible reactions between detected species can help to understand the evolution in complexity of the interstellar matter and also allows knowing the formation of new molecules which could be...
Article
Theoretical methodologies have been employed to study [Mg,C,N,O] isomers which are possible species of interstellar interest. It has been found that, at all levels of theory used, the most stable isomer is magnesium isocyanate radical. The corresponding cyanate counterpart lies 15.8 kcal/mol, at CCSD(T) level of theory, above MgNCO. Other isomers s...
Article
Chemistry in the interstellar medium (ISM) is capable of producing complex organic molecules (COMs) of great importance to astrobiology. Gas phase and grain surface chemistry almost certainly both contribute to COM formation. Amino acids as building blocks of proteins are some of the most interesting COMs. The simplest one, glycine, has been charac...
Article
A theoretical study of monoboronyls of different metals has been carried out. We have chosen Mg as representative of s-block elements, Al for the p-block, and Group 11 metals (Cu, Ag, and Au) for the d-block. Different behaviors are observed: bonding through the oxygen atom is preferred in the case of Al, for all Group 11 monoboronyls bonding throu...
Article
The metallic cyanoacetylides CuCCCN, AgCCCN, and AuCCCN have been synthesized in the throat of a pulsed supersonic expansion by reaction of metal vapors, produced by laser ablation, and BrCCCN. Their pure rotational spectra in the (X(1)Σ(+)) electronic ground state were observed by Fourier transform microwave spectroscopy in the 2-10 GHz frequency...
Article
Iron is the most abundant transition metal in space. Its abundance is similar to that of magnesium, and until today only, FeO and FeCN have been detected. However, magnesium-bearing compounds such as MgCN, MgNC, and HMgNC are found in IRC+10216. It seems that the hydrides of iron cyanide/isocyanide could be good candidates to be present in space. I...
Article
We show, by means of direct dynamics simulations, how it is possible to define possible reactants and mechanisms leading to the formation of formamide in the interstellar medium. In particular, different ion–molecule reactions in the gas phase were considered: NH 3 OH + , NH 2 OH + 2 , H 2 COH + , and NH 4 + for the ions and NH 2 OH, H 2 CO, and NH...
Article
The most relevant species of plutonium tricarbide have been characterized employing theoretical methods. The global minimum is predicted to be a fan structure, where the plutonium atom is bonded to a quasilinear C3 unit. A rhombic isomer, which is shown to be a bicyclic species with transannular C-C bonding, lies about 39 kJ/mol above the fan isome...
Article
Context. One of the most interesting questions in interstellar chemistry concerns whether we can detect the basic building blocks of proteins in astronomical sources. In ascertaining whether amino acids could be possible interstellar molecules, a crucial point is how they could be synthesized in the interstellar medium. Aims. We do a theoretical st...
Article
The structure and spectroscopic parameters of the most relevant [C,H,N,Zn] isomers have been studied employing high-level quantum chemical methods. For each isomer, we provide predictions for their molecular structure, thermodynamic stabilities as well as vibrational and rotational spectroscopic parameters which could eventually help in their exper...
Article
Full-text available
Combined spectroscopy measurements and theoretical calculations bring to light a first investigation of a metallic cyanoacetylide, AlC3N, using laser ablation molecular beam Fourier transform microwave spectroscopy. This molecule was synthesized in a supersonic expansion by the reaction of aluminum vapour with C3N, produced from solid aluminum rods...
Article
Full-text available
A theoretical study of the reactions of with formaldehyde and with formamide is carried out. The viability of these gas-phase ion-molecule reactions as possible sources of formamide and acetamide under the conditions of interstellar medium is evaluated. We report a theoretical estimation of the reaction enthalpies and an analysis of their potential...
Article
Full-text available
The reactions, in the gas phase, between alkali-earth monocations (Mg(+), Ca(+), Sr(+), Ba(+)) and CH3X (X = Cl, Br) have been theoretically studied. The stationary points on the potential energy surfaces were characterized at the Density Functional Theory level on the framework of the mPW1K functional with the QZVPP Ahlrichs's basis sets. A comple...
Article
Full-text available
The molecular structure of methanediol has been investigated by means of quantum chemical calculations. Two conformers, corresponding to C2 and C s symmetries, respectively, were considered. The C2 conformer is found to lie about 1.7 (at 298 K) or 2.3 (at 0 K) kcal mol–1 below the C s conformer. Predictions for their rotational constants, vibration...
Article
Full-text available
We study the viability of different gas-phase ion-molecule reactions that could produce precursors of formamide in the interstellar medium. We analyze different reactions between cations containing a nitrogen atom (NH_{3}^{+}, NH_{4}^{+}, NH3OH+, and NH2OH+) and neutral molecules having one carbonyl group (H2CO and HCOOH). First, we report a theore...
Article
Thermodynamics and kinetics theoretical studies on the gas-phase reactions of fluoromethane with main-fourth-period mono-cations (Ga+, Ge+, As+ and, Se+) have been carried out. Density functional theory (in particular mPW1K functional) was employed in the description of the potential energy surfaces and refinement of the energies were done at the C...
Article
Full-text available
A computational study of peptide bond formation from gas-phase ion-molecule reactions has been carried out. We have considered the reaction between protonated glycine and neutral glycine, as well as the reaction between two neutral glycine molecules for comparison purposes. Two different mechanisms, concerted and stepwise, were studied. Both mechan...
Article
In this article, the most relevant isomers of uranium tricarbide are studied through quantum chemical methods. It is found that the most stable isomer has a fan geometry in which the uranium atom is bonded to a quasilinear C3 unit. Both, a rhombic and a ring CU(C2) structures are found about 104-125 kJ∕mol higher in energy. Other possible isomers i...
Article
The gas-phase reactivity of methyl fluoride with selected first-row transition metal monocations (Sc(+), Ti(+), V(+) and Zn(+), ) has been theoretically investigated. Our thermochemical and kinetics study shows that early transition-metal cations exhibit a much more active chemistry than the latest transition metal monocation Zn(+), . The strong C-...
Article
Full-text available
The molecular structures of third-row main group tricarbides C(3)X (X = K-Br) have been studied by quantum chemical methods. It is found that less electronegative elements (K, Ca, Ga, Ge) favor either fan or rhombic structures (resulting from side interactions with either linear or triangular C(3) units), whereas the more electronegative elements (...
Article
The dipole moments of Na n clusters in the size range 10 < n < 20, recently measured at very low temperature (20 K), are much smaller than predicted by standard density functional methods. On the other hand, the calculated static dipole polarizabilities in that range of sizes deviate non-systematically from the measured ones, depending on the emplo...
Article
Full-text available
A computational study of the reactions of hydroxylamine and its ionized and protonated derivatives with acetic acid is provided. The reaction of neutral hydroxylamine with acetic acid, despite being clearly exothermic, involves a very large energy barrier. The reaction of ionized hydroxylamine with acetic acid is also clearly exothermic, but again...
Article
A theoretical study of the molecular structure of uranium dicarbide has been carried out employing DFT, coupled cluster, and multiconfigurational methods. A triangular species, corresponding to a (5)A(2) electronic state, has been found to be the most stable UC(2) species. A triplet linear CUC species, which has been observed in recent infrared spe...
Article
A computational study of the reaction of P(+)((3)P) with acetylene has been carried out. The only exothermic products correlating with the reactants are PCCH(+)((2)Π) + H((2)S). Two different pathways leading to these products that are apparently barrier-free have been found. Both pathways involve isomerization into open-chain intermediates followe...
Article
A theoretical study of neutral Zn[CN]n and Cu[CN]n complexes has been carried out, as representative examples of cyanide complexes of late transition metals. Both complexes prefer the cyanide arrangement over the isocyanide form, in agreement with the experimental evidence for the monocyanide compounds. The successive complexation energies suggest...
Article
Full-text available
Reactions of methyl fluoride with bare alkaline-earth metal monocations (Mg+, Ca+, Sr+, and Ba+) were studied using theoretical methods. Thermochemical data were calculated using density functional theory in conjunction with polarized 3-ζ and 4-ζ basis sets. Variational/conventional microcanonical transition state theory was used for the calculatio...
Article
Neutral iron-cyanide complexes have been studied through computational techniques. Fe[CN]n complexes are shown to prefer the cyanide arrangement. Only in the case of Fe[CN] the isocyanide isomer is found to lie slightly below the cyanide isomer. According to the complexation energies, Fe(CN)2 seems to be the main target for possible experimental ob...
Article
Full-text available
The molecular structures of third-row main group dicarbides C(2)X (X=K-Br) have been studied by theoretical methods. It is found that K, Ca, and Ga favor C(2v)-symmetric (T-shape) ground states, whereas As, Se, and Br have linear or quasilinear ground states. In the case of germanium. a very flat potential energy surface is found and an L-shape str...
Article
A theoretical study of the reactions of CH3NH2+/CH3NH3+ with formic acid has been carried out in order to clarify their role in the formation of glycine derivatives under the conditions of the interstellar medium. The possible intermediate species as well as the relevant transition states for these reactions were characterized at the MP2 level with...
Article
Full-text available
Context. The formation of glycine is strongly relevant to our understanding of the interstellar medium and is most accuretely studied computationally. Aims: We carry out a theoretical study of the reactions between the radical cation of ammonia and CH3COOH/CH2COOH as possible processes leading to glycine derivatives. Methods: The gas-phase reaction...
Article
A computational study of arsenic dicarbide has been carried out. In agreement with the experimental evidence theoretical calculations predict a 2Π ground state. However, a cyclic 2B2 species is found just about 3–4kcal/mol higher in energy. The 2B2 species is shown to be a true minimum with a predicted barrier for isomerization around 7–8kcal/mol....
Article
Density functional theory (B3LYP) and coupled-cluster techniques [CCSD(T)] including solvent effects have been used to study the homoleptic and mixed cyanide/isocyanide complexes of Ti(IV), [Ti(CN)(n)](4-n) (n=1-6). The most stable isomer is found to be the isocyanide form except for n=6 where the cyanide isomer is preferred. Calculations accountin...
Article
The stability of protonated and ionized hydroxylamine in relation to their reactivity with molecular hydrogen has been studied. All stationary points and transition states for the reactions of H2 with protonated and ionized hydroxylamine have been determined at the MP2(full) level with the cc-pVTZ basis set. Energetic data have been obtained at the...
Article
Neutral Ti[CN](n) complexes have been investigated with quantum chemistry techniques. According to our theoretical predictions, these complexes are shown to prefer isocyanide arrangements. Therefore, these compounds are good candidates to be the first polyisocyanides to be characterized. The theoretical calculations predict Ti(NC)(4), a methane-lik...
Article
A theoretical study of the ion-molecule reaction, NH(2)(+) with acetic acid that could lead to precursors of glycine in the interstellar medium, has been carried out on the triplet and singlet potential energy surfaces. All stationary points and transition states on the (NO(2)C(2)H(6))(+) triplet and singlet surfaces have been determined at the MP2...
Article
The structures and molecular properties of open-chain and cyclic ZnCn+/− (n = 1–8) clusters have been calculated by hybrid density functional theory. Equilibrium geometries, electronic energies, vibrational frequencies, dipole moments and rotational constants for individual species are provided. Some energetic aspects related to these clusters, suc...
Article
The structure and properties of the different linear, fan and cyclic isomers of CoCn+ and CoCn− (n=1–8) clusters have been calculated using the B3LYP method with the 6–311+G(d) basis set. The stability of clusters as a function of the size has been discussed in terms of the incremental binding energies. Linear, fan and cyclic structures of CoCn+ cl...
Article
A theoretical study of the different linear, fan and cyclic CoCn (n = 1–8) clusters has been carried out. Predictions for their electronic energies, rotational constants, dipole moments, and harmonic vibrational frequencies have been made using the B3LYP method with the 6-311+G(d) basis set. Doublet and quartet lowest-lying states have been found f...
Article
A theoretical study of the [FeCN]+ system has been carried out. Density functional methods, as well as single- and multi-reference techniques, were employed. Both cyanide and isocyanide isomers are very close in energy, with FeCN+ lying about 0.9kcalmol−1 below FeNC+. A non-linear minimum, with iron formally bonded just to the nitrogen atom accordi...
Article
A theoretical study of the first-row transition metal dicarbide cations MC2+ (M=Sc-Zn) has been carried out. Predictions for different molecular properties that could help in their eventual experimental detection have been made. Most MC2+ compounds prefer a C2v symmetric arrangement over the linear geometry. In particular, the C2v isomer is special...
Article
Cyanides and isocyanides of first-row transition metal M(CN) (M=Sc-Zn) are investigated with quantum chemistry techniques, providing predictions for their molecular properties. A careful analysis of the competition between cyanide and isocyanide isomers along the transition series has been carried out. In agreement with the experimental observation...
Article
A theoretical study of the different fan and cyclic isomers of VCn+/− (n=2–8) clusters has been carried out. Predictions for different molecular properties, such as electronic energies, harmonic vibrational frequencies or rotational constants, have been made using the B3LYP method with different basis set including effective core potentials, ECPs....
Article
A theoretical study of the small ZnCn (n = 1−8) clusters has been carried out at the B3LYP/6-311+G(d) level. Different molecular properties for open-chain and cyclic species have been calculated. The computed properties include electronic energies, vibrational frequencies, dipole moments, and rotational constants for individual species. In addition...
Article
A computational study of the N(4S) + CH3 reaction has been carried out. The reactants approach through an attractive potential surface leading to an intermediate, H3CN, whose formation does not involve any barrier. In agreement with the experimental results, the dominant channel for this reaction is H2CN+H. The theoretically estimated rate coeffici...
Article
First-row transition-metal dicarbides MC(2) (M=Sc-Zn) have been investigated by using quantum-mechanical techniques. The competition between cyclic and linear isomers in these systems has been studied and the bonding scheme for these compounds is discussed through topological analysis of electron density. All of the systems have been found to prefe...
Article
The singlet potential energy surface for the N(2D) + CH2Br reaction has been studied employing both MP2 and DFT(B3LYP) methods. The energies of the involved species have been refined using the G2, CBS and CCSD(T) methods, respectively. The reaction proceeds through the formation of an initial intermediate which does not involve any activation barri...
Article
A DFT theoretical study of the VCn+, and VCn− (n=1–8) open-chain clusters has been carried out using the B3LYP method. Results for several molecular properties which could help in their possible experimental characterization, such as equilibrium geometries, electronic energies, dipole moments, and vibrational frequencies are provided. For the VCn+...
Article
A theoretical study of the binary titaniumcarbon cations TiC2+ and Ti2C4+ has been carried out. The TiC2+ global minimum is a T-shaped C2v-symmetric structure corresponding to a 2A2 electronic state, whereas the lowest-lying linear isomer lies about 20 kcal/mol higher in energy. In the case of Ti2C4+ the ground state corresponds to the 4Bu state of...
Article
A computational study of the reaction of CH2Cl radicals with N(2D) atoms has been carried out. The most exothermic products result from elimination of either HCl or H2, instead of elimination of either Cl or H. The preferred channel is predicted to be HCN+HCl. The analysis of the possible spin crossing between the triplet and singlet [CH2NCl] poten...
Article
A theoretical study of the ScCn, ScCn+, and ScCn- (n = 1-10) cyclic clusters has been carried out employing the B3LYP density functional method. Predictions for several molecular properties that could help in their possible experimental characterization, such as equilibrium geometries, electronic structures, dipole moments, and vibrational frequenc...
Article
A theoretical study of the different isomers of neutral VCn (n = 1−8) clusters has been carried out. Predictions for their electronic energies, rotational constants, dipole moments, and vibrational frequencies have been made using the B3LYP method with different basis sets. For linear and cyclic VCn clusters, the lowest-lying states correspond to q...
Article
A computational study of the reaction of N(4S) with CH2Br radicals has been carried out. The reaction starts through the formation of a relatively stable intermediate which does not involve an energy barrier. The two most exothermic products are those resulting from the release of a bromine atom, H2C=N+Br and trans-HC=NH+Br. A kinetic study, within...